Immediately, we have established the simpler physical choice for the momentum transfer potential between the dark sectors, which happens
when \(f_{A}=0\)  in the rest-frame of either DM or DE [1]}. Consequently, this choice allows two different possibilities
for \(Q_{A}^{\mu }\)  and \(f_{A}\) , which can be parallel to either the DM or the DE four velocity, respectively. In this work, we focus only on
the case
[1]}, [3]}
\({Q}_{DE}^{\mu }={\bar{Q}}_{DE}U^{\mu }_{DM}&=&-{Q}_{DM}^{\mu },\quad Q^{\mu }_{A}\parallel U^{\mu }_{DM},\qquad \nonumber \\f_{DM}=\frac{{\bar{Q}}_{A}}{k^{2}}(\theta -\theta _{DM})&=&-f_{DE}\,,\,\quad Q^{\mu }_{A}\parallel U^{\mu }_{DM},\) 
